Dusk Till Dawn Lab

Dusk Till Dawn

• Objective
• Measurements
• Conclusion

Objective
        The objective of this lab is to use a transistor and a photocell to control an LED. In essence, we are making a night light. 

    

Measurements

Photoresistor Voltages
Resistor(kΩ)	Theory (V)	Measured (V)	% Difference
5.00	1.68	1.81	-6.99
20.00	3.35	1.94	72.68
7.00	2.08	1.94	7.07

   

       

Conclusion

       There was a sizable discrepancy between the measured and calculated voltages at the 20k resistance. I am thinking this is probably because the resistor doesn't get anywhere to close to 20k. In fact, I added a projection for when the resistor is closer to 7k and the difference falls closer to 7%, similar to the 5k assumption from the first trial. I assume this tells that the photocell acutally has a much more narrow range of values than assumed.